Sprzedawczyni powiedziała, że bez paragonu możliwa jest tylko reklamacja.

Sprzedawczyni means female shop assistant / saleswoman.

Polish often marks the gender of the person more clearly than English does. Here:

• sprzedawca = a male shop assistant / salesman
• sprzedawczyni = a female shop assistant / saleswoman

So the sentence tells us that the speaker is referring specifically to a woman.

Because the subject, sprzedawczyni, is feminine.

In the Polish past tense, the verb agrees with the gender of the subject:

• powiedział = he said
• powiedziała = she said

So:

• Sprzedawca powiedział... = The salesman said...
• Sprzedawczyni powiedziała... = The saleswoman said...

This is a very common feature of Polish past-tense verbs.

Że means that.

It introduces a subordinate clause, just like English that in sentences such as:

• She said that...
• The teacher said that...

So:

• Sprzedawczyni powiedziała, że... = The saleswoman said that...

In English, that is often optional, but in Polish że is normally used in this kind of sentence.

Because bez (without) requires the genitive case in Polish.

So:

• dictionary form: paragon = receipt
• after bez: bez paragonu = without a receipt

This is a standard pattern:

• bez cukru = without sugar
• bez problemu = without a problem
• bez biletu = without a ticket
• bez paragonu = without a receipt

So the change is not random: it happens because of the preposition bez.

Yes, paragon usually means a shop receipt / sales receipt.

In everyday Polish, paragon is the normal word for the paper proof of purchase you get in a store.

So bez paragonu means without the receipt or without a receipt.

Reklamacja is a bit broader than the English word complaint.

In a shopping context, reklamacja usually means a claim about a faulty product, for example when you ask the seller to:

• repair it,
• replace it,
• refund it,
• or otherwise deal with a defect.

So in this sentence, reklamacja is not just complaining in a general sense. It refers to a formal consumer claim about a product.

A useful distinction:

• zwrot = return
• reklamacja = complaint/claim based on a fault or defect

Możliwa agrees with reklamacja, which is a feminine singular noun.

• reklamacja = feminine singular
• so the adjective must also be feminine singular:
  • możliwy = possible (masculine)
  • możliwa = possible (feminine)
  • możliwe = possible (neuter)

So:

• możliwa jest reklamacja = a complaint/claim is possible

This agreement is very important in Polish.

Both are possible. The difference is mainly word order and emphasis, not basic meaning.

The original sentence:

• możliwa jest tylko reklamacja

sounds natural and slightly formal. It puts early focus on possible.

Another version:

• tylko reklamacja jest możliwa

also means only a complaint/claim is possible, but the emphasis is a bit more directly on only reklamacja.

Polish word order is more flexible than English, so different orders can sound natural depending on what is being emphasized.

Here jest means is.

• możliwa jest tylko reklamacja = only a complaint/claim is possible

In the present tense, Polish often omits to be in some sentence types, but not usually in this structure. Here jest sounds normal and expected.

You would not normally say:

• bez paragonu możliwa tylko reklamacja

in standard neutral Polish. It would sound incomplete or elliptical.

So in this sentence, jest should stay.

Because Polish has no articles.

English distinguishes between:

• a receipt
• the receipt

but Polish does not have separate words for that. The exact meaning depends on context.

So:

• bez paragonu can mean without a receipt or without the receipt
• tylko reklamacja can mean only a complaint/claim or only the complaint/claim option

You understand which one is meant from the situation.

It is natural, but somewhat official / customer-service-like in tone.

It sounds like something a shop assistant might say when explaining store policy or legal rights.

A more everyday version might be something like:

• Bez paragonu można tylko złożyć reklamację.
• Bez paragonu możliwa jest wyłącznie reklamacja.

The original sentence is perfectly normal, just a little more formal and structured.

Yes, but that would change the meaning.

• zwrot = return
• reklamacja = complaint/claim about a defective item

So:

• bez paragonu możliwa jest tylko reklamacja means you cannot simply return the item; you can only make a defect-based claim.

If you said:

• bez paragonu możliwy jest tylko zwrot

that would mean only a return is possible, which is a different idea.

So the choice of reklamacja is important.

Yes, that is possible, but it is a bit different stylistically.

• Bez paragonu możliwa jest tylko reklamacja
  = more noun-based, more formal, more official

• Bez paragonu można tylko reklamować
  = more verb-based, a bit more direct, closer to everyday speech

Both express roughly the same idea, but the original sounds more like a store rule or policy statement.